1. Field of the Invention
The present invention relates to fire suppression systems. More specifically, the invention is a system that detects removal of a cartridge or canister from a fire suppression system and is operative to prevent the door of an enclosure from closing for so long as the cartridge is removed and the fire suppression system inoperative, and provides a visible, audible or electrical indication of the removal of the cartridge.
2. Description of the Related Art
Fire suppression systems are common in commercial environments. Such systems are typically situated proximal to the most probable ignition sources, such as stoves, friers, grills, and the like, in restaurant environments.
Active fire protection devices typically fall within one of two groups: single vessel stored-pressure systems and cartridge-operated systems. In single vessel stored-pressure systems, an expellant is stored in the same vessel as the firefighting agent itself. For example, the typical wall-mounted fire extinguisher is a single-vessel stored-pressure system that incorporates either pressurized nitrogen or pressurized air in the same vessel as the expellant (e.g., dry chemical, dry powder, water and foam, etc.).
Cartridge operating systems, however, are most likely to be installed in commercial and industrial areas because they are simpler and faster to recharge compared to stored-pressure systems. These types of systems may or may not include a single vessel that includes both the expellant and the firefighting agent. In some systems, opening the cartridge simply actuates the opening of a separate stored-pressure vessel, while in other systems the pressure may be contained within the cartridge itself.
Despite the simplicity and quick recharge of cartridge-operated systems, it can still be expensive to maintain, perhaps costing hundreds of dollars for a certified technician to visit the facility and perform maintenance services, such as recharging the system. As a result, persons who might be working around the fire suppression systems (e.g., cleaning crew) are often tempted to remove, and sometimes do remove, the cartridge from the system to prevent accidental discharge and the subsequent costly recharge service call. In addition, the cartridge typically must be removed during each regular inspection of the system, leaving open the possibility that the inspecting technician may fail to reinstall the cartridge prior to conclusion of the inspection, and thus leave the system inoperative.
In one 2010 restaurant fire, for example, the fire suppression system never activated. After the fire was extinguished, the cartridge was found unconnected to the system and sitting in the bottom of the enclosure housing the suppression system controls. While unconfirmed, those familiar with the situation suspected that someone had removed the cartridge to prevent accidental discharge and then forgot to reconnect the cartridge. The restaurant owners sued everyone, including the fire inspection business that last inspected the system. Unfortunately, there was no independent mechanism in place to confirm that the cartridge was properly installed at the conclusion of the most-recent inspection of the system.